docker: Hide scary-looking but harmless tar failure messages.

* guix/docker.scm (build-docker-image): Wrap "tar --delete" invocation
in 'with-error-to-port'.

1 files changed, 7 insertions, 2 deletions

diff --git a/guix/docker.scm b/guix/docker.scm
index c19a24d45c..c6e9c6fee5 100644
--- a/guix/docker.scm
+++ b/guix/docker.scm
@@ -209,8 +209,13 @@ SRFI-19 time-utc object, as the creation time in metadata."
         ;; the path "/a" into "/".  The presence of "/" in the archive is
         ;; probably benign, but it is definitely safe to remove it, so let's
         ;; do that.  This fails when "/" is not in the archive, so use system*
-        ;; instead of invoke to avoid an exception in that case.
-        (system* "tar" "--delete" "/" "-f" "layer.tar")
+        ;; instead of invoke to avoid an exception in that case, and redirect
+        ;; stderr to the bit bucket to avoid "Exiting with failure status"
+        ;; error messages.
+        (with-error-to-port (%make-void-port "w")
+          (lambda ()
+            (system* "tar" "--delete" "/" "-f" "layer.tar")))
+
         (for-each delete-file-recursively
                   (map (compose topmost-component symlink-source)
                        symlinks))